Process for the production of an article for the cladding of floors or walls

Abstract

A process for the production of an article for the cladding of floors or walls, comprising the steps of, in a mold: a) optionally applying a gel coat layer, based on a first curing polymer resin, on the inside of the mold in order to obtain a coated mold, and b) introducing into the core of the mold or into the core of the coated mold from step a) a filling composition which is based on a second curing polymer resin supplemented with at least one mineral filler, wherein core contains at least 5% wt and at most 20% wt of curing polymer resin, relative to the dry amount of filling composition, and the filling composition contains only one single initiator in a concentration of 0.5% wt to 5.0% wt relative to the amount of curing polymer resin in the filling composition.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A process for the production of an article for the cladding of floors or walls, comprising the steps of in a mold:
 a) optionally applying a gel coat layer, based on a first curing polymer resin, on the inside of the mold in order to obtain a coated mold, 
 b) introducing into the core of the mold or into the core of the coated mold from step a) a filling composition which is based on a second curing polymer resin supplemented with at least one mineral filler, 
 wherein the core of the article has a thickness of at least 20 mm, the filling composition for the core contains at least 10% wt and at most 20% wt of curing polymer resin, relative to the dry amount of the filling composition, and the filling composition contains methyl ethyl ketone peroxide as the only one single initiator in a concentration of 0.5% wt to 5.0% wt relative to the amount of curing polymer resin in the filling composition, 
 whereby the curing reaction of the filling composition is initiated at ambient temperature. 
 
     
     
       2. The process according to  claim 1 , wherein the core of the article has a thickness of at least 25 mm. 
     
     
       3. The process according to  claim 1 , wherein the core is fiber-reinforced. 
     
     
       4. The process according to  claim 1 , wherein the core contains at most 19% wt of curing polymer resin. 
     
     
       5. The process according to  claim 1 , wherein the second curing polymer belongs to the family of unsaturated polyester polymer resins, and wherein for the curing reaction a vinyl monomer has been incorporated. 
     
     
       6. The process according to  claim 5  for reducing the concentration of the vinyl monomer that is remaining in the article. 
     
     
       7. The process according to  claim 5  for a purpose selected from improving the industrial hygiene for the people installing the article and improving the fire performances of the article. 
     
     
       8. The process according to  claim 1 , comprising step a) wherein the first and the second curing polymer resins belong to the same chemical family of curable polymeric resins. 
     
     
       9. The process according to  claim 1 , comprising step a) wherein the gel coat layer in the coated mold of step a) is only cured partially before the coated mold of step a) is subjected to step b). 
     
     
       10. The process according to  claim 9 , wherein the curing polymer resin of step a) is cured only until the gel coat layer is at most touch dry, before the coated mold of step a) is subjected to step b). 
     
     
       11. The process according to  claim 1 , comprising step a) wherein the first curing polymer resin belongs to the family of unsaturated polyester polymer resins, and wherein for the curing reaction a vinyl monomer has been incorporated. 
     
     
       12. The process according to  claim 11 , wherein the first curing polymer resin has a gel time of at least 10 minutes. 
     
     
       13. The process according to  claim 1 , comprising step a) wherein the gel coat layer in step a) comprises at least one initiator. 
     
     
       14. The process according to  claim 1 , wherein the filling composition for the core in step b), and/or, if step a) is present the gel coat layer in step a), further comprises an accelerator for the curing reaction. 
     
     
       15. The process according to  claim 1 , wherein the mineral filler in step b) is selected from the group consisting of quartz, sand, dolomite powder, and mixtures or combinations thereof. 
     
     
       16. The process according to  claim 15 , wherein the dolomite powder has a pH of at most 9.5. 
     
     
       17. The process according to  claim 1 , wherein the mineral filler in step b) comprises a mixture of a first filler with grains which have an average diameter in the range of 0.5-5 mm, with a second filler with fine grains having an average diameter in the range of 50-500 μm. 
     
     
       18. The process according to  claim 1 , wherein the mold before step b), or before step a) if the process comprises step a), is treated with a release agent. 
     
     
       19. The process according to  claim 18 , wherein the release agent comprises a polymeric resin, dissolved in an aliphatic hydrocarbon solvent. 
     
     
       20. The process according to  claim 1 , comprising step a) wherein the gel coat layer is applied by a technique selected from the group consisting of spreading, spraying, and combinations thereof. 
     
     
       21. The process according to  claim 1 , wherein to the polymer resin of the core and/or of the gel coat layer at least 0.5% and at most 20% by weight is added, expressed on the basis of the total amount of polymer resin in the gel coat layer or in the core, of an additional unsaturated polyester resin which is characterized by an elongation at break after curing of the resin and tested according to ISO 527 of at least 4.0%. 
     
     
       22. The process according to  claim 1 , wherein the filling composition further contains a substance which is selected from a group consisting of a dye, a pigment, paint flakes, metal flakes, and combinations thereof. 
     
     
       23. The process according to  claim 1 , comprising step a) wherein the gel coat layer further contains a substance which is selected from a group consisting of a dye, a pigment, a filler, paint flakes, metal flakes, and combinations thereof. 
     
     
       24. The process according to  claim 1 , comprising step a) wherein the partial curing of the gel coat layer comprises the storage of the coated mold in an environment with a temperature in the range of from 10° C. to 50° C. 
     
     
       25. The process according to  claim 1 , wherein the filling composition for step b) is obtained by first dry blending of the mineral filler material, if present with other dry ingredients of the filling composition, followed by the injection of the curing polymer resin, preferably as a mixture which possibly shortly before the injection was mixed with the initiator and/or with at least one and all of the other liquid ingredients of the filling composition, and subsequently mixing of the liquid and the solid ingredients of the filling composition, by a worm wheel or an Archimedes screw which brings the filling composition while mixing at or above the coated mold. 
     
     
       26. The process according to  claim 1 , wherein as part of step b) after the introduction of the filling composition into the core of the coated mold the mold is vibrated, possibly in more than one period, with each time an interval, between which the mold may be transferred to another location, and wherein the vibration occurs at a frequency of a number of cycles per minute which is in the range of 10 to 600 cycles per minute, and for a total vibration time which is in the range of 15 seconds to 2 minutes. 
     
     
       27. The process according to  claim 1 , wherein as part of step b), upon introduction of the filling composition into the core of the coated mold the amount of introduced filling composition is limited in such a way that, if present after shaking, it fills at least 100% of the remaining free volume of the mold and not exceeding 105% of that remaining free volume.